Telephone system



H. HOVLAND- 2,216,532

TELEPHONE SYS TEM 0st. I, 1940.

Filed March 20, 19s? 5 4 Sheets-Sheet 1 FIG! lNl ENTOR H. HOVLAND A TTORNK V TELEPHONE SYSTEM Filed March 20. 1937 4 Sheets-Sheet 2 llllllllllllll INVENTOR By HHOVLA/VD Oct. 1, 1940. H. HOVLAND TELEPHONE SYSTEM Filed March 20, 1937 4 4 Sheets-Sheet 5 /N 5 N TOP :2; By HHOVLAND Oct. 1, 1940. H H VL AND 2,216,532

TELEPHONE SYSTEM Filed March 20, 1937 4 Sheets-Sheet 4 CONNEC TING PLUG nsaumso ONLY WHEN TWO ausr TONE co/vos/vsms n SHELF ARE mow/0E0.

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(hi com -CAELE- r0 PEN V REGISTERS PLU & JACK CONNECT/0N r0 PEN nsc- ISTER. PA TCN/NG CORD INVENTOR H. HO VLAND WKWM ATTORNEY Patented Oct. 1, 1940 UNITED STATES PATENT OFFICE Application March 20, 1937, Serial No. 132,009

14 Claims.

This invention relates to telephone systems and particularly to systems in which automatic switches are employed for establishing connections between calling and called lines.

It is the object of the invention to facilitate the recording of trailic data in automatic telephone systems and to provide means for indicating whether or not a subscriber is in need of one or more additional lines.

This invention is a line-busy recording equipment comprising a register common to a group of final selector or connector switches and means for operatively connecting the register to only one of the connector switches at a time. Ac- 'cording to a feature of the invention two registers are provided with selective switching means for operatively connecting any one of a group of connectors to one of the registers and at the same time operatively connecting any other one of the connectors in the group to the other of the registers. According to another feature of the invention, a line-busy recording equipment comprises a register common to a group of connector switches and means effective upon seizure of any one of said connectors for operatively connecting the register to the seized switch.

The invention will be more easily understood by considering a telephone system arranged in accordance therewith, one such system being shown schematically in the-drawing which forms a .part of this specification. The invention is, however, not limited in its application to the particular system shown but is, in general, applicable to any telephone system in which autoas matic switching equipment is employed in establishing connections with called subscribers lines.

Referring to the drawings,

Fig. '1 shows a calling subscriber's line LI and station.A, a line-finder switch LF, first selector switch S, two connector switches Cl and C2 of a group of connectors, and a called subscribers line L2 and station B;

Fig. 2 shows a register selector RS together with a jack box 2I3 and plug-ended cords for use in connecting the recorder equipment to a group of ten connectors;

Fig. 3 shows two register control relay groups RA and RB, a busy and timing relay group BT and two pen registers PRA and PRB; and

Fig. 4 shows a frame of connectors and a portable line-busy recording equipment.

The subscribers sets at stations A and B are of the usual type employed in automatic telephone systems and include dial impulse senders 55 for use in establishing connections with any other station with which connection is desired. The line-finder switch LF', selector S, and connectors CI and C2 are of the well-known two-motion step-by-step type. For a description of the structure of such switches and their operation when used as selectors and connectors, reference may be had to pages 53 to 61 inclusive of the second edition of Automatic Telephony by Smith and Campbell; For a description of the operation of such a switch when used as a line finder, reference may be had to Patent 1,799,654 granted to R. L. Stokely, April 7, 1931. The line finder LP is represented by a single set of brushes and one set of terminals, and the selector S is represented by a set of brushes and two sets of terminals; all operating magnets and relays associated with'switches LF and'S are omitted. Theconnector switch CI is represented by a set of brushes and a single set of terminals, the associated magnets and relays being shown;- the connector C2 is represented by a set of brushes, a single set of terminals and two of the associated relays;

The register selector RS, register control relay groups RA and RB, and the'busy and timing relay group BT are preferably-mounted as a unit on wheelsyas shown in Fig. 4, so as to be readily movable to any desired and convenient position. The register selector RS comprises ten sets of control relays, one for each of ten connectors and two additional control relays, relay 230 for the relay group RA and relay 250 for the relay group RB. Only three of these sets of control relays are shown; the relays 22I, 23I and 25I are associated with jack 2!; the relays 222, 232 and 252 are associated with jack 202; and the relays 223, 233 and 253 are associated with jack 2); the other seven sets of relays are indicated by the broken lines between relays 232 and 233 and between relays 252 'and 253 and by the seven intermediate sets of contacts on relays 230 and 250. Ten jacks and ten cords are provided for connecting the register selector to any group of ten connectors. Three of these jacks 2M, 202 and 2H) and two of the cords MI and I42 are shown in Figs. 1 and 2. The cords terminate in plugs at the register selector and control unit and in connecting clips or special connecting plugs at the connector end. Two additional jacks 2H and 2I2 and cords l5l and I52 are provided for connecting the busy and timing relay group BT to the ringing current conductors and the busy tone leads of the shelf of connectors to which the ten cords including cords I4I, I42 are connected. If only one busy tone lead is provided for the ten connectors on a shelf, only one.

of the two conductors of cord I52 is used. The ten jacks represented by jacks 20I, 202 and 2I0 and the two jacks 2H and 2I2 are mounted in a jack box 2I3 which is carried by, but removable from, the register selector and control unit; a twelve pair cable 2M is provided for connecting the jack box to the control unit. This arrangement permits the jack box to be placed close to the connector frame on which is located the ten connectors to be connected to the register selector and control unit, while the control unit is located at an advantageous position remote from this connector frame. A jack is provided on the control unit for supplying battery and ground to the relays and magnets; a patching cord 2I5 is used to connect this jack to any convenient source of battery and ground potential, for instance to a battery and ground supply jack 2I6 on the connector frame as shown in Fig. 4. The pen registers PRA and PRB are removably mounted on the relay unit and connected thereto by a four-wire cord 360. To facilitate connection and disconnection of the pen registers, jacks, plugs, or keys may be used to terminate the cord 360 and the conductors of the relay groups and pen registers. As shown in Fig. 4, the cord 360 is key connected to the pen registers and plug and jack connected to the relay unit. This arrangement permits the placing of the pen registers in a desired location remote from the relays. Each of the pen registers comprises two pens, one for marking on the tape the impulses ofthe last two digits of the number of a called line and the other for marking on the tape the busy condition if this called line is busy. The impulse recording pen is also operated to make a long dash after the units digit has been recorded or to make a similar dash if the timing relays f group BT and one of register groups RA or RB complete the measurement of a predetermined interval of time after the operative association of a connector therewith, before the tens and units digits have been received and recorded. The busy tmarking pen may mark the tape if the brushes pass over busy lines during their advance to the terminals of the called line, but makes a long dash on the tape when the associated connector finds-the called line busy.

Assume the line LI to have been connected, by the operation -of switches LF and S and any intermediate selectors (none shown), to the connector CI. Upon seizure of connector CI, the line relay IN is operated by the current in a circuit from battery through the lower winding of relay IOI, inner lower back contact of relay I04, middle terminal and brush of each of switches S and LF, over the lower conductor of line LI, through the telephone .at station A, back over the upper conductor of line L I, top terminal and brush of switches LF and S, upper back'contact of relay I04, and through the upper winding of relay IOI :to ground. Relay 'IOI closes a circuit for operating the slow-to-release relay I02; and relay I02 connects ground, through its inner lower from contact, to sleeve conductor IIO to mark connector 01 busy .in the banks of other selectors and to hold the switches S and LF in usual manner.

When the subscriber at station A dials the next to the last digit of the number of the station B with which .connection is desired, relay I0'I releases at each interruption of its circuit by the dial. The first release of relay IOI closes a circuit for operating relay I03 and vertical-stepping magnet III; this circuit is traced from battery through the winding of magnet III, winding of relay I03, normally closed contact of the vertical off-normal springs VON, upper front contact of relay I02, to ground at the back contact of relay IOI. The operation of magnet I II raises the brushes H1, H3 and H9 up to the first level of the bank, the VON springs being actuated as soon as the shaft moves out of normal position. After relay I03 operates and the VON springs are actuated, the operating circuit for magnet I I I and relay I03 includes the front contact of relay I03 and upper front contact of springs VON instead of the normally closed con.- tact of the VON springs. Being slow in releasing, relay I02 remains operated during the response of relay IOI to dial impulses and relay I03 remains operated until all of the impulses in the train have been received. The operation of magnet !I I in response to each dial impulse, steps the brushes up to the level corresponding to the digit dialed. When relay I03 releases, the rotarystepping magnet I I2 and relay I05 are connected to the impulse contact of relay IOI; this connection is traced through the upper front contact of relay I02, upper front contact of the VON springs, back contact of relay I03, lower back contact of relay I0'I, to the winding of relay !05, and through the inner upper back contact of relay I08 to the winding of magnet II2.

Each release of relay I M in response to the impulses created by the dialing of the last digit of the called stations number is therefore effective to energize relay I05 and magnet I I 2. Each operation of magnet II2 rotates the brushes H1, H8 and I!!! one step in the selected level, the terminals of the called line being thereby selected. The operation of relay I05 connects the winding of busy-test relay I0I to sleeve brush H9; this connection is traced through the lower back contact of relay I08 and the upper front contact of relay E05. Relay I05 is slow in releasing and, after its operation in response to the first impulse, it remains operated until all of the impulses in the train have been received. The operation of relay I07, in case brush IIS engages the terminal of a busy line during advance of the brushes to the terminals of the called line, does not interfere with the further operation of magnet II2 since the lower front contact of relay I 05 is in parallel with the lower back contact of relay ID'I. If the called line is idle, brush II9 encounters a battery potential and busy test relay I0'I does not operate; and, when relay I05 releases, a. circuit is closed from this battery potential through brush H9, upper outer back contact of relay I05, lower winding of relay I00, upper back contact of relay I01, to ground at the inner lower front contact of relay I02. Relay I08 is sufficiently energized by the current through its lower winding to actuate its inner upper front contact and thereby close a circuit through its upper winding to ground at the lowermost front contact of relay I02. Relay I08, completely operated by the energization of its upper winding connects ground through its lowermost front contact and sleeve brush I I9 to the sleeve terminal of the called line to mark the line as busy. Relay I08 also closes a circuit from ringing current source I09 through the inner lower front contact of relay I08, lower winding and lower back contact of relay I06, middle lower front contact of relay I08, brush H8, lower conductor of line L2, through the ringer (not shown) at station B, upper conductor of line L2, brush III, outer upper front contact of relay I08, and through the upper back contact of relay I00 to ringing source ground. When the receiver is removed at station B, relay I 06 is sumciently energized by the current through its lower winding to close its inner upper front contact and thereby energize its upper winding. The complete operation of relay I06 connects the windings of relay I04, through the outer front contacts of relay I05, front contacts of relay I08, and through brushes H1 and H8 to the line L2. Relay I04 operates and remains operated under the control of the called station while relay I 0| remains operated under control of the calling station, the talking circuit .being completed through condensers I2I and I22. When both the calling and called subscribers replace the receivers, relays IM and I04 release. The release of relay ISI causes the release of relay I02 thereby disconnecting ground from conductor I I0 to release the preceding switches in usual manner. With both of relays I02 and I04 released. relays I00 and I08 release. The release of relay I08 closes a circuit for operating release magnet II3; this circuit is traced. from ground at the back contact of relay llll, through the upper back contact of relay I02, upper most back contact of relay I08, lower contact of the VON springs and the winding of magnet H3 to battery. The

operation of magnet II3 restores the switch to normal in usual manner; If only the called subsciiiber releases the connection, ground is connected to conductor I23; and if only the calling subscriber releases the connection, ground is connected to conductor I24. In either case an a arm is operated in usual manner, if both subscribers have not releasedwithin a predetermined interval such as from twenty to forty minutes.

If the called line L2 happens to be busy when the brushes of switch CI are advanced into engagement with the terminals of this line, the ground potential, marking the line as busy, causes the operation of test relay I01. When relay I05 releases, relay I01 is held operated through the lowermost back contact of relay I08, inner back contact of relay I05, inner front contact of relay I01, to ground at the inner lower front contact of relay I02. Busy tone is transmitted from source H4 through condenser II5, outer front contact of relay I01, and through condenser I22 to the calling station. When the calling subscriber releases, relays NH and I02 release, relay I01 releases, magnet II3 operates, and the switches-LP, S and CI are restored to normal.

If now the connector CI .is connected by cord I4I to jack 20I, the operation of relay I02. upon seizure of connector CI connects ground through its inner lower front contact, over one of the conductors of cord I4I to the ring of jack 20I and connects the back contact of line relay IOI, through the upper front contact of relay I02, over the other conductor of cord I4I to the tip of jack 20! Assuming that neither of registers PRA and PRB is then operatively engaged, the ground at the inner lower front contact of relay I02 is further connected through the ring conductor of jack 20I and back contact of relay 22I, uppermost back contact of relay 230, winding and back contact of relay 23I, and through the lower back contact of relay 230 to battery. Relay 23I operates and it locks through its inner left front contact, the back contacts of relay 232 and the corresponding intermediate relays, to battery at the back contact of relay 233. This chain locking circuit prevents the locking of more than one of relays 23I, 232, 233 if two connectors in the group are seized simultaneously. At its middle right front contact, relay 23I connects the tip conductor'of jack 20I, over conductor 234, through resistor 330 to the winding of impulse relay 33I of the register control relay group RA; and at its outer right front contact, relay 23I connects the winding of relay 22I to and through the ring conductor of jack 20I to the ground at relay I02. Relay 22I operates and it locks through its inner right front contact to the same ground. Relay 22I closes a circuit for holding relay 23I and operating relay 320 of the relay group RA; this circuit is traced from ground through the winding of relay 320 and back contact of relay 336 of relay group RA, over conductor 235, left outer front contact of relay 22I, inner right front contact and winding and inner left front contact of relay 23 I, thence to battery at the back contact of relay 233. At its outer right front contact, relay 22I closes a circuit, which includes the left outer front contact of relay 23 I, for operating relay 230. The operation of relay 230 disconnects the windings of relays 232 and 233 and the seven intermediate relays from the'ring conductors of the associated jacks and connects the windings of relays 252 and 253 and the seven intermediate relays to these con-ductors so that, if another of the connectors in the group is seized while relay group RA is operatively associated with connector CI, this other connector will be connected over conductors 254 and 255 to relay group RB by the operation of the associated one of relays 252 and 253 and the seven intermediate relays, the operation of the corresponding one of relays 222 and 223 and the seven intermediate relays, and the operation of relay 250 in the same manner in which relays 22I, 23I and 230 are operated as hereinbefore described. In this case a circuit is closed for holding the opera'ted one of relays 252 and 253 and intermediate relays and for operating relay 340, this circuit being similar to that above described for holding relay 23I and operating relay 320. If any other connector is'seized while both of the pen registers are operatively engaged, the corresponding one of the relays, similar to relay 22 I, is operated through front contacts of relays 250 and 230; but this other connector is not connected to either of the register groups RA or RB since the two associated relays, similar to relays 23I and 25I, are not operated and cannot be operated to connect one of the register uni-ts to the connector in question. If one of relays 22I, 222, 223 operates at a time when both of the pen registers are operatively engaged, it is held operated until the associated connector releases so that, if one of the pen registers becomes idle before this connector is released, this connector will not be operatively connected to the idle register.

Assuming the connector CI to have been seized and connected to register group RA as herein before described, the response of relay IOI to the impulsescreated by the dialing of the penultimate digitof the called subscribers number causes relay 33I to be operated and released a corresponding number of times. Resistor 330 prevents the operation of relay 33I from excessive interference with the stepping magnets of the connector switch. At its right front contact, relay 33I closes a circuit for operating the magnet 36I of register PRA to register each of the impulses. At its left front contact, relay 33I closes a circuit for operating relay 332; and, being slow in releasing, relay 332 remains operated until all of the impulses in the series have been received and registered. Upon its operation, relay 332 closes a ciroperating relay 333.

relays 311 and 312.

cuit for operating relay 333. At itsfront contact, relay 333 closes a circuit through its winding and the winding of relay 334, in series, to ground at the left front contact of relay 320; but the winding of relay 334 is short-circuited. through the right back contact of relay 334 and front contact of relay 332 until relay 332 releases. When relay 332 releases, relay 334 operates and both of relays 333 and 334 are locked operated under control of relay 325. When the last digit of the called subscribers number is dialed, the response of relay 101 .to each impulse is repeated to relay 331; and each operation of relay 331 again closes the circuit for operating magnet 331 to register these impulses. The reoperation of relay 332, during the response of relay 331 to the impulses of the last digit, closes a circuit through the front contact of relay 334 for operating relay 335. Relay 335 locks through its inner right front contact to ground at the left front con-tact of relay 320. When relay 332 releases after all of the impulses in the train have been received and registered, a circuit is closed through the back contactof relay 332 and inner left front contact of relay 335 for The operation of relay 336 disconnects the winding of relay 320 from conductor 235, thereby causing the release of relay 320, and connects conductor 235 to ground at the outer right front contact of relay 335. At its outer left front contact, relay 336 connects ground to the inner front contact of relay 315; andat its inner left front contact relay 333 connects ground to the winding of pen register magnet 361. The release of relay 3211 causes the release of relays 333, 334 and 335; and the release of relay 335 causes the release of relay 333.. Since relay 336 is slow in releasing, the release of relay 335 also causes the release of relay 231 of the register selector. When relay 336 releases, pen register magnet 331 releases. The dash recorded on the tape of the pen register, during the time that relay 333 is operated indicates that both of the tens and units digits were fully recorded.

If now the connector G1 has tested and found the called line busy, ground is connected through the lower winding of relay 134, outer front contact of relay 1131, through the associated conductors of cord 152 and jack 212, to the winding of relay 313 or to the winding of relay 314. The operation of either relay 313 or relay 314 causes the operation of relay 315. With relay 315 operated and with either of relays 335 and 336 operated, ground is connected to the winding of magnet 352 of pen register PRA to record the busy condition of the called line. If any of the other connectors in the group are transmitting busy tone, relay 315 will be operated even though the line encountered by connector C1 is idle; but, if this is the case, the busy mark starts when relay 335 operates responsive to the first impulse of the units digit whereas if this is not the case the long dash indicating a busy line starts at the same time as the dash which indicates that dialing is completed. Relay 315 is slow in operating to delay the operation of busy recording magnet 362 and thereby distinguishes between a case in which the last digit of the called number is 1 and the called line is busy and a case in which the last digit is 1 and some other connector in the group is at that time transmitting busy tone.

If now after seizure of connector C1, the last digit of the called subscribers numberis not dialed within an interval or from 12 to 18 seconds, the register is released by means of timing Relay 311 is operatedfonce every six seconds-by ringing current from the ringing supply of the group of connectors to which jacks 201, 232, 203 are connected, over the conductors of cord 151, through jack 21 I and condenser 3'10 and the winding of relay 31 1. Each operation of relay 311 closes a circuit for operating relay 312. Relay 312 closes a circuit through the inner right front contact of relay 320 and the back contact of relay 322 for operating relay 32'1. Relay 321 closes a circuit through its winding and front contact and winding of relay 322 to'ground at the left front contact of relay 320. Until relays 311 and 312 release at' the end of the usual two-second ringing period, the winding of relay 322 is short-circuited; but, when relay 312 releases, relay 322 operates and is locked in series with relay 321 under control of relay 320. When relays 31 1 and 312 reoperate during the next ringing period, relay 312 closes a circuit through the front contact of relay 322 and back contact of relay 324, for operating relay 323. When relay 312 again releases relay 324 is operated and locked in series with relay 323 to ground at relay 320. At the end of the following silent interval, relays 311 and 312 are again operated by the ringing current; and relay 312 closes a circuit through front contacts of relays 320, 322 and 324 for operating relay 335. The operation of relay 335 is followed by the operation of relay 336, release of relay 3211,

release of relay 335, release of relay 231, and the release of relay 336 as hereinbefore described. So that, if at the end of an interval of from 12 to 18 seconds after the operation of relay 323, the last two digits of the called number have not been registered and relay 335 operated, relay 335 is operated by the timing relays to effect disconnection of the pen register PRA and relay group RA from the connector C1.

The release of relay 231, due to'the operation of relay'336' either when the tens and units digits have been recorded or when the predetermined interval has elapsed as above described, causes the release'ofrelay 230', but relay 221 is held operated through the ring conductor of jack 2111 and conductor of cord 141 to ground at the front contact of relay 132 of connector 01 so that a pen register cannot be twice connected to this connector on one call. The register relay group RB functions to connect a connector to register PRB in the same manner that group RA functions to connect a connector to register PRA as above described.

What is-claimed is:

1. In a signaling system comprising lines and a group of connector switches, each connector operative to select any one of said lines, an electromagnetic recorder, and switching means for operatively connecting the recorder to any one of said switches, said recorded being effective upon connection with a switch to record the number ofthe line selected by said switch and to record that the selected line is busy if such is thecase.

2. In a signaling system comprising lines and a group of connector switches for selecting called lines, means for seizing and selectively operating any one of said switches, a busy-line recorder common to said switches, means responsive to the F seizure of any one of said connectors on a call from one to another of said lines for operatively associating saidseized connector and said recorder and means in said recorder for recording the number of the lineselected by said seized connector.

3. In a signaling system comprising lines and connector switches for use in selecting called lines and means for extending connections from calling lines to said connectors, a called line number recorder, means comprising cords and jacks for associating said recorder with the connectors having access to any particular group of lines, and relays efiective upon seizure of any one of said connectors on a call from one to another of said lines for operatively connecting the seized connector to said recorder.

4. In a signaling system comprising lines and a group of switches for selecting any one of said lines, a plurality of recorders less in number than the switches in said group, each of said recorders comprising means for recording the number of the line selected by any one of said switches and for recording that the selected line is busy if such should be the case, and means for operatively connecting each of said recorders to any one of said switches.

5. In a signaling system comprising lines and a group of switches for selecting any one of said lines, means for seizing and selectively operating any one of said switches, a plurality of recorders less in number than the switches in said group, each of said recorders comprising means for recording the number of the line selected by any one of said switches and for recording that the selected line is busy if such should be the case, and means responsive to seizure of any one of said switches for operatively connecting the seized switch to an idle one of said recorders.

6. In a signaling system according to claim 1, means for releasing the operative connection between any one of said connectors and said recorder.

7. In a signaling system according to claim 1, means for releasing the operative connection between any one of said connectors and said recorder, and means for preventing a second con.- nection between any one of said connectors and said recorder while the connector in question continues to engage the same line.

8. In a signaling system according to claim 2, means responsive to the recording of 'thenumber of the selected line for releasing the operative association between any one of said connectors and said recorder.

9. In a signaling system according to claim 2, means responsive to the recording of the number of the selected line for releasing the operative association between any one of said connectors and said recorder, and means for preventing a second association between any one of said connectors and said recorder while the connector in question continues to engage the same line.

10. In a signaling system according to claim 1, means effective a predetermined interval of time after the operative connection of any one of said connectors to said recorder for releasing said connection.

11. In a signaling system according to claim 1, means eifective a predetermined interval of time after the operative connection of any one of said connectors to said recorder for releasing said connection, and means for preventing another operative connection between any one of said connectors and said recorder until after the connector in question has been released for use on another call.

12. In a signaling system according to claim 2, means responsive to the recording of the number of a selected line or efiective a predetermined interval of time after the operative association of any one of said connectors and said recorder for releasing said operative connection.

13. In a signaling system according to claim 2, means responsive to the recording of the number of a selected line or effective a predetermined interval of time after the operative association of any one of said connectors and said recorder for releasing said operative connection, and means for preventing a second association between any one of said connectors and the recorder until after the connector in question has been released for use on another call.

14. In a telephone system, lines, agroup of impulse controlled connector switches for selecting called lines, means for seizing and operating an idle one of said connectors, a recorder common to said switches, means individual to each of said connectors and responsive to seizure of the associated connector for operatively associating said connector and said recorder, means in said recorder for recording the directive impulses received by an associated connector, means in said recorder for recording the busy condition of the line selected by an associated connector when such a condition exists, means responsive to completion of the recording of the directive impulses by which an associated one of said connectors is operated to select a desired line or effective a predetermined interval of time after the operative association of a connector and the recorder for releasing the connection between the connector and the recorder, and means individual to each of said connectors for preventing a second association of a connector and said recorder until after said connector has been released for use on another call.

. HENRY HOVLAND. 

